Cutting Device, Method and Use for Cutting of a Line Extending from a Floating Vessel

ABSTRACT

Cutting device, method and use are for cutting of a line extending from a floating vessel. The cutting device is structured for placement on the vessel. The cutting device comprises: at least one guide structured for directional steering of the line past a cutting area for the line; and at least one of the following cutting-promoting devices: at least one induction coil device directed inwards toward the cutting area and structured for heating, hence weakening, of the line within the cutting area; and at least one moveable cutting knife with an opposite contact surface directed inwards toward the cutting area and also structured for cutting of the line within the cutting area.

AREA OF INVENTION

The present invention concerns a cutting device, a method and a use forcutting of a line extending from a floating vessel.

For example, the vessel may be comprised of a boat or a floatinginstallation. As an example, the boat may be comprised of an anchorhandling vessel, whereas the floating installation may be comprised of adrilling rig or a drilling ship. Said line may be comprised of, forexample, a chain, a wire or a fibre line, possibly an assembly of suchline types.

It is to be possible, by means of the present invention, to carry out aquick, controlled and safe cutting of the line on board the vessel, forexample in an emergency situation. In order to avoid damage to personneland equipment, remote-controlled cutting may also be carried out.

BACKGROUND OF THE INVENTION

The background of the invention is emergency situations that haveoccurred at sea in context of handling big loads from floating vessels,particularly during bad weather conditions. Under such conditions, a bigload may become unmanageable, for example displaced, whereby the vesseland its crew are at risk of becoming seriously damaged and/orshipwrecked.

Particularly in context of towing and relocation of mobile installationsat sea, it is customary to use so-called anchor handling vessels. Suchvessels comprise spooling apparatuses for spooling of chains, fibrelines and/or wires. The purpose of such a vessel may be to tow afloating installation to a particular position and then to anchor theinstallation to the seabed by means of a suitable mooring system.

Typically, such a mooring system will comprise a line having a lower endconnected to a large and heavy anchor, and having an upper end carriedback to the installation. The line may also be a compound line and thuscomprise portions of length consisting of different types of line ofdifferent shape and/or material type, for example a chain, a fibre lineand/or a wire. Thereby, the line may also be of a more or less flexibleconstruction.

For placement and pulling of such an anchor, the associated line will beattached to a spooling apparatus, the apparatus of which generally isdisposed at the forward end of the deck of the anchor handling vessel.The line extends from the spooling apparatus, further across the deckand down into the water at the aft end of the vessel. During such ananchor handling operation, the total weight of the anchor and the linemay amount to several hundred tonnes. Chain links made of steel, whichare used in this context, may possibly have a transverse dimension inthe order of 5-10 cm and may a weight in the order of 100-200 kg/meter.

During such an anchor handling operation, however, unforeseen incidentsmay arise causing the vessel to become exposed to unmanageable forcesvia the line attached to the vessel. For example, it may relate to theline displacing itself over the side of the vessel and causing it tobecome lop-sided, which at worst may cause the vessel to capsize andpossibly sink.

An example of the latter is the vessel Bourbon Dolphin which, during ananchor handling operation offshore Shetland on Apr. 12, 2007, capsizedand finally sunk at a depth of ca. 1100 meters. Several of the vessel'screw members perished in context of the capsizing. The vessel was in theprocess of pulling up a so-called Bruce anchor attached to a chain andwire having a total weight in the order of 200-300 tonnes.

In view of such unfortunate and disastrous incidents associated withload-burdened lines extending from floating vessels, it would thereforebe very advantageous if such lines could be severed as fast as possiblein a controlled and safe manner for personnel and equipment, for examplevia remote control. It would also be advantageous if it was possible tocut all types of line potentially being used on a particular vessel, forexample a chain, a fibre line and/or a wire. A technical solution which,when in an emergency situation, brings about such severing possibilitieswould be able to limit adverse effects and possibly prevent disasterscausing crew members, the vessel and/or equipment to perish.

PRIOR ART

The applicant does not know of any dedicated, technical solution forcutting of a line extending from a floating vessel in context ofuncontrollable management of the load on the line. Common practice insuch a situation is for the crew to leave as fast as possible from thearea within which the line is affected by the uncontrollable load, andthat attempts are possibly made of cutting the line by means of acutting torch or similar. Such an attempt, however, involves a very bigrisk to the crew carrying out the cutting.

OBJECT OF THE INVENTION

The primary object of the invention is to provide a technical solutionfor allowing cutting of a line extending from a floating vessel, forexample in an emergency situation.

It is also an object of the invention to provide a technical solutionwherein the cutting may be carried out quickly and in a safe mannerpreventing damage to personnel on board the vessel.

HOW TO ACHIEVE THE OBJECT

The object is achieved by virtue of features disclosed in the followingdescription and in the subsequent claims.

According to a first aspect of the invention, a cutting device forcutting of a line extending from a floating vessel is provided, whereinthe cutting device is structured for placement on the vessel. Thedistinctive characteristic of the cutting device is that it comprises:

-   -   at least one guide structured for directional steering of the        line past a cutting area for the line; and    -   at least one of the following cutting-promoting devices:        -   at least one induction coil device directed inwards toward            the cutting area and structured for heating, hence            weakening, of the line within the cutting area; and        -   at least one moveable cutting knife with an opposite contact            surface directed inwards toward the cutting area and also            structured for cutting of the line within the cutting area.

Thereby, the cutting device may comprise at least one induction coildevice and/or at least one moveable cutting knife with an oppositecontact surface.

If required or desirable, the vessel may be provided with several suchcutting devices for cutting of several lines extending from the vessel.

For example, said line may be comprised of at least one chain, a metalwire and a fibre line. Further, the cutting area may be arranged withinthe at least one guide. The cutting area may also be placed on or near adeck on the vessel. Yet further, the line, for spooling thereof, may beconnected to a spooling apparatus placed on the vessel.

According to a first embodiment, the cutting device may comprise:

-   -   at least one guide structured for directional steering of a        metallic line past the cutting area; and    -   at least one induction coil device directed inwards toward the        cutting area and also structured for line-severing heating,        hence weakening, of the metallic line within the cutting area.

In this first embodiment, no cutting knife/knives is/are used, but onlyone or more induction coil devices. For example, when a load-burdened,metallic line, e.g. a wire or a chain, extends from the vessel andcutting is required, the at least one induction coil device will be ableto quickly heat, hence weaken, the line within the cutting area. Eventhough the very heating will be able to melt the line and thus sever theline, the load on the line will stretch the line at the same time andwill contribute to weaken the line faster and further until the line issevered.

According to a second embodiment, the cutting device may comprise:

-   -   at least one guide structured for directional steering of the        line past the cutting area and    -   at least one moveable cutting knife with an opposite contact        surface directed inwards toward the cutting area and also        structured for cutting of the line within the cutting area.

In this second embodiment, no induction coil device(s) is/are used, butonly one or more moveable cutting knives. Also in this secondembodiment, the load on the line will contribute to weaken the linefaster and further until the line is severed.

According to a third embodiment, the cutting device may comprise:

-   -   at least one guide structured for directional steering of a        metallic line past the cutting area;    -   at least one induction coil device directed inwards toward the        cutting area and structured for heating, hence weakening, of the        metallic line within the cutting area; and    -   at least one moveable cutting knife with an opposite contact        surface directed inwards toward the cutting area and also        structured for cutting of the line within the cutting area.

The preceding comments to the first and second embodiment of the cuttingdevice are also applicable to this third embodiment.

According to a fourth embodiment, which comprises a cutting device withat least one induction coil device, the line may comprise a chaincomposed of chain links, wherein the cutting device is structured forcutting of a chain link within the cutting area and comprises:

-   -   at least one first induction coil device structured for heating,        hence weakening, of a first side of the chain link; and    -   at least one second induction coil device structured for        heating, hence weakening, of a second side of the chain link.

In all embodiments comprising a cutting device with one or moreinduction coil devices, the at least one induction coil device may beconnected to a moving means structured to be moveable inwards toward thecutting area for the line. Thereby, also the one induction coil devicewill be moveable toward the cutting area.

Alternatively, at least one non-moveable induction coil device, which isstructured in a manner allowing it to embrace the line fully orpartially, may be used. Thereby, the line will be able to extend throughthe non-moveable induction coil device during spooling of the line. Suchan induction coil device may be structured so as to be mountable anddemountable, whereby the induction coil device may be easily assembledaround the line prior to handling thereof and also to be demounted afterhandling of the line.

The cutting device may also comprise an electric power source onto whichthe at least one induction coil device is connected. Thus, the electricpower source may be comprised of the electric power supply of the vesseland/or of at least one battery.

According to a fifth embodiment, which comprises a cutting device withat least one cutting knife, the at least one cutting knife may beconnected to a moving means structured to be moveable inwards toward thecutting area for the line. Thereby, also the cutting knife will bemoveable toward the cutting area.

According to a sixth embodiment, which also comprises a cutting devicewith at least one cutting knife, said contact surface for the at leastone cutting knife may be comprised of a cooperating cutting knife. Inthis context, cooperating cutting knives may be arranged in a scissorconfiguration for cutting of the line. Alternatively, such cooperatingcutting knives may be aligned directly opposite each other, i.e. theedges of the knives are axially directed with respect to each other.Further, said contact surface cutting knife may be connected to a movingmeans structured to be moveable inwards toward the cutting area of theline. Thereby, also the contact surface cutting knife will be moveabletoward the cutting area.

Moreover, said contact surface for the at least one cutting knife mayhave any suitable shape, including a planar surface.

According to a seventh embodiment, which also comprises a cutting devicewith at least one cutting knife, the line may comprise a chain composedof chain links, wherein the cutting device is structured for cutting ofa chain link within the cutting area and comprises:

-   -   at least one first, moveable cutting knife with an opposite        contact surface structured for cutting of a first side of the        chain link; and    -   at least one second, moveable cutting knife with an opposite        contact surface structured for cutting of a second side of the        chain link.

In this seventh embodiment, the first cutting knife and the secondcutting knife may be connected to a moving means structured to bemoveable inwards toward the cutting area for the line. Thereby, also thefirst and second cutting knife will be moveable toward the cutting area.

Further, the contact surface of the first cutting knife may be comprisedof a third cutting knife structured for cutting-cooperation with thefirst cutting knife, whereas the contact surface of the second cuttingknife is comprised of a fourth cutting knife structured forcutting-cooperation with the second cutting knife.

Yet further, the first cutting knife and the third cutting knife may bearranged in a scissor configuration for cutting of the first side of thechain link, whereas the second cutting knife and the fourth cuttingknife are arranged in a scissor configuration for cutting of the secondside of the chain link.

Furthermore, the third cutting knife may be connected to a moving meansstructured to be moveable toward the first cutting knife, whereas thefourth cutting knife is connected to a moving means structured to bemoveable toward the second cutting knife. Thereby, also the third andfourth cutting knife will be moveable toward the cutting area.

In context of cutting chain links, the applicant has shown, via tests,that it is possible to sever chain links in steel having a diameter of20 mm, 56 mm and 76 mm, and only by means of cutting knives of suitableshape. Among other things, cutting knives having different angles andshapes of the knife edge were tried during the tests. In this context,opposite cutting knives having knife edge angles of 35°, 60°, 75° and90°, respectively, were used, among other things. The knife edge shapeproved to have relatively little influence on the cutting force used forthe different diameters of chain links. The essential thing was to beable to prove that it was possible to carry out a fast cutting ofheavy-duty chain links only by means of suitable cutting knives. Apotential heating and weakening of a chain link by means of at least oneinduction coil device would thus further increase the effectiveness ofthe cutting.

According to an eight embodiment, the cutting device may also compriseat least one fixing device for fixing of the line during cuttingthereof. As such, the fixing device may comprise a recoil brake orrecoil clutch structured for engagement with the line. As an addition oralternative, the fixing device may comprise a releasable lockingmechanism structured for locking engagement with the line, for exampleat least one gripping element adapted for gripping of the particulartype of line.

Advantageously, the fixing device may also be disposed between the atleast one cutting-promoting device of the cutting device and a fasteningdevice of the line on the vessel. Disposed in this manner, the fixingdevice will be able to fix the line both during the cutting and afterthe severing thereof, whereby a potentially damaging backlash of theline is prevented.

The cutting device and the fixing device may also be connected to asupport, wherein the support is connected to a moving means structuredso as to be moveable in the moving direction of the line.

In this manner, the fixing device may be disposed in a particularposition relative to the line, for example centred directly opposite achain link. Then the Fixing device may be brought into engagement withthe line at a particular location for correct fixing of the line at thislocation. By so doing, the fixing device may, for example, be conveyedinto an opening in a chain link, as shown on FIGS. 8 and 10 in thesubsequent exemplary embodiment.

In this manner, the cutting device is also structured, to a certainextent, in a manner allowing it to travel along, if required in anemergency situation, in the moving direction of the line should the linebe moving during the cutting thereof. Thereby, the cutting deviceremains stationary relative to the line during the very cuttingoperation. Movement of the line during the cutting, however, is not adesired situation and, if possible, the line should be kept at restrelative to the vessel during the very cutting operation.

Said support may be comprised of a support structure, for example asupporting platform which, via the moving means, is structured so as tobe moveable along a deck on the vessel. In one embodiment, this may becarried out by virtue of the support structure being connected to thedeck of the vessel via at least one guide element, for example at leastone rail, track, pulley or similar structure, which is directed in themoving direction of the line. Further, the fixing device may bestructured for remote-controlled activation and operation.

Moreover, the at least one moving means mentioned in the precedingembodiments may comprise a moveable piston. This piston may be drivenmechanically, hydraulically, pneumatically or electrically and possiblybe disposed in an associated piston cylinder. As an addition oralternative, the at least one moving means may comprise a pitch rackguide, for example in the form of a pinion/toothed gear connected to atoothed bar/rack (“rack and pinion”) or similar.

The present cutting device may also be structured for remote-controlledactivation and operation, which will increase the personnel safety onboard the vessel, among other things.

According to a second aspect of the invention, a method for cutting of aline extending from a floating vessel is provided. The distinctivecharacteristic of the method is that it comprises the following steps:

-   -   placing at least one cutting device on the vessel, the cutting        device comprising the following features:        -   at least one guide structured for directional steering of            the line past a cutting area for the line; and        -   at least one of the following cutting-promoting devices:            -   (a) at least one induction coil device directed inwards                toward the cutting area and structured for heating,                hence weakening, of the line within the cutting area;                and            -   (b) at least one moveable cutting knife with an opposite                contact surface directed inwards toward the cutting area                and also structured for cutting of the line within the                cutting area;    -   conveying the line through said guide and cutting area; and    -   when cutting of the line is required, activating at least one of        said cutting-promoting devices (a) and (b) and severing the line        within the cutting area.

Thereby, the cutting may be carried out by means of at least oneinduction coil device and/or at least one cutting knife with an oppositecontact surface.

For example, said line may be comprised of at least one chain, a metalwire and a fibre line.

In context of the present method, reference is also made to detailsdescribed hereinbefore in context of the present cutting device.

According to a first embodiment, the method may comprise the followingsteps:

-   -   placing the at least one induction coil device on the vessel;    -   conveying a metallic line through said guide and cutting area;        and    -   when cutting of the metallic line is required, activating the        induction coil device and heating, hence weakening, the metallic        line within the cutting area until severing the line.

In this first embodiment of the method, the cutting is carried outsimply by means of one or more induction coil devices.

According to a second embodiment, the method may comprise the followingsteps:

-   -   placing the at least one moveable cutting knife with an opposite        contact surface on the vessel;    -   conveying the line through said guide and cutting area, the        cutting area being located between the cutting knife and the        opposite contact surface; and    -   when cutting of the line is required, moving the at least one        cutting knife toward the opposite contact surface until severing        the line.

In this second embodiment of the method, the cutting is carried outsimply by means of one or more cutting knives.

According to a third embodiment, the method may comprise the followingsteps:

-   -   placing both the at least one induction coil device and the at        least one moveable cutting knife on the vessel;    -   conveying a metallic line through said guide and cutting area,        the cutting area being located between the cutting knife and the        opposite contact surface;    -   when cutting of the metallic line is required, activating the        induction coil device and heating, hence weakening, the metallic        line within the cutting area and moving the at least one cutting        knife toward the opposite contact surface until severing the        line.

In this third embodiment of the method, the cutting is carried out bymeans of at least one induction coil device and at least one cuttingknife. In this context, the metallic line may be heated, hence weakened,prior to the line being cut by the at least one cutting knife.Alternatively, the metallic line may be heated, hence weakened, at thesame time as the line is cut by the at least one cutting knife.

According to the method, the cutting device may be placed on or near adeck on the vessel.

The line may also be connected to a spooling apparatus placed on thevessel for spooling of the line.

Further, the cutting device may also comprise or be connected to afixing device for fixing of the line during cutting thereof.Advantageously, this fixing device may be disposed between the at leastone cutting-promoting device of the cutting device and a fastening pointof the line on the vessel.

Yet further, the cutting device and the fixing device may be connectedto a support, and the support may be connected to a moving meansstructured so as to be moveable in the moving direction of the line. Byso doing, the fixing device may travel along in the moving direction ofthe line during the cutting thereof, whereby the cutting device remainsstationary relative to the line during the very cutting operation. Inthis context, said support may be comprised of a support structurearranged so as to be moveable along a deck on the vessel.

Moreover, the cutting device and/or the fixing device may be activatedand operated by means of remote control, which increases personnelsafety on board the vessel.

According to a third aspect of the invention, a use of a cutting devicefor cutting of a line extending from a floating vessel is provided,wherein the cutting device comprises:

(a) at least one guide structured for directional steering of the linepast a cutting area for the line; and(b) at least one of the following cutting-promoting devices:

-   -   at least one induction coil device directed inwards toward the        cutting area and structured for heating, hence weakening, of the        line within the cutting area; and    -   at least one moveable cutting knife with an opposite contact        surface directed inwards toward the cutting area and also        structured for cutting of the line within the cutting area.

In this context, reference is also made to details describedhereinbefore in context of the present cutting device and method.

Hereinafter, a non-limiting exemplary embodiment of the presentinvention will be shown.

SHORT DESCRIPTION OF FIGURES OF THE EXEMPLARY EMBODIMENT

FIG. 1 is a perspective drawing of an anchor handling vessel providedwith a cutting device according to the invention, wherein the figurealso shows a section box around the cutting device;

FIG. 2 shows, in larger scale, the section box from FIG. 1;

FIGS. 3 and 4 show, in larger scale, a front elevation and a base view,respectively, of the cutting device according to FIGS. 1 and 2,including a fixing device for gripping and fixing of a chain link in thechain, and also other associated equipment;

FIGS. 5 and 6 show, in larger scale, a front elevation and a base view,respectively, of the cutting device whilst a chain is conveyed past thecutting device and said fixing device, insofar as the plan view is seenalong section line VI-VI in FIG. 5;

FIGS. 7 and 8 show, in larger scale, a front elevation and a base view,respectively, of the cutting device whilst a vertically standing, secondchain link is located in a suitable position for allowing it to begripped and fixed by said fixing device, insofar as the plan view isseen along section line VIII-VIII in FIG. 7;

FIGS. 9 and 10 show, in larger scale, a front elevation and a base view,respectively, of the cutting device whilst the second chain link isbeing fixed by the fixing device, and after having conveyed twoinduction coil devices inwards toward respective sides of a horizontallylying, first chain link so as to be in the process of heating the sidesof the chain link, insofar as the plan view is seen along section lineX-X in FIG. 9;

FIG. 11 shows, in larger scale, a front elevation of the cutting deviceimmediately after two sets of cooperating cutting knives having severedthe respective, heated sides of the first chain link;

FIG. 12 shows, in even larger scale, a section of FIG. 11 around thecutting area of the first chain link; and

FIG. 13 shows said section after having removed the cutting knives fromsaid cutting area.

The figures are schematic and may be somewhat distorted with respect torelative size and relative placement of components constituting parts ofthe exemplary embodiments of the invention. In general, identical orcorresponding details of the figures will be denoted with the same orsimilar reference numerals in the following.

EXEMPLARY EMBODIMENT OF THE INVENTION

FIGS. 1 and 2 show an anchor handling vessel 2 with a deck 4 which, atthe forward end thereof, is provided with, among other things, a cuttingdevice 6 according to the invention and a large guide wheel 8 arrangedbetween the cutting device 6 and a cabelar wheel (not shown) at theforward end of the deck 4. Via the guide wheel 8, a very heavy dutychain 10 may be spooled out or in via the cabelar wheel. The chain 10 isspooled out from/into a cargo hold (not shown) within the vessel 2. Thefunction of the guide wheel is to guide the chain 10 correctly into thecutting device 6. The chain 10 extends from the forward to the aft endof the deck 4 and onwards over the stern 12 and down into the sea 14where the chain 10 is connected to a large and heavy anchor 16.

For directional steering of the chain across the deck 4, the deck 4 isalso provided with a support pillar 18 at the forward end thereof, andalso two guide pegs 20 at the aft end thereof between which the chain 10extends.

In this embodiment, the cutting device 6 is placed on a supportingplatform 22 which is connected in a moveable manner to two rails 24disposed on the deck 4, and in the moving direction of the chain 10across the deck 4. The rails shown in FIGS. 1 and 2 are schematic and,in practice, may have any suitable length. For longitudinal movement ofthe platform 22, it may be connected to one or more pistons, pitch rackguides, motors, control units and similar (not shown) providing andcontrolling the movement. In this embodiment, the movement of theplatform 22 is activated and operated interactively via remote control.For this purpose, the platform 22 is also provided with at least onesurveillance camera and at least one light source (not shown). As analternative or addition, the platform movement may be controlled more orless automatically through suitable control technology and associatedmeans therefor. Thereby, the cutting device 6 may, if required, travelalong in the moving direction of the chain 10 during the cuttingthereof, whereby the cutting device remains stationary relative to thechain 10 during the very cutting operation. As mentioned above, however,movement of the line during the cutting is not a desired situation and,if possible, the line should be kept at rest relative to the deck 4during the very cutting operation. Also the cutting device 6 isactivated and operated by means of remote control.

As shown in FIGS. 3 and 4, the cutting device 6 comprises, among otherthings, two guides 26 a and 26 b, i.e. one guide on each side of thecutting device 6, for conveying the chain 10 via the cutting device 6and past a cutting area 28 thereof. The pay out direction of the chain10 is toward the left in FIGS. 3 and 4.

The cutting device 6 also comprises several cutting-promoting devicesstructured in a manner allowing them to separate/sever a horizontallylying, first chain link 30 in the chain 10. By means of said guides 26a, 26 b, the chain link 30 will be disposed horizontally prior to thesecutting-promoting devices being activated for separation/severing of thechain link 30. In this embodiment, the cutting-promoting devices arecomprised of both induction coil devices and cutting knives, and all ofthese devices are structured so as to be moveable inwards toward thecutting area 28.

As such, the cutting device 6 comprises a first induction coil device 32a and an oppositely directed, second induction coil device 32 b. Bothinduction coil devices 32 a, 32 b are directed horizontally inwardstoward the cutting area 28 and may be moved in this direction forheating and weakening of the first chain link 30 within the cutting area28. Thereby, the first induction coil device 32 a may heat up a firstside 30 a of the chain link 30, whereas the second induction coil device32 b may heat up a second side 30 b of the chain link 30. In order to bemoved horizontally inwards toward the cutting area 28, each inductioncoil device 32 a, 32 b is connected to a respective piston rod 34 a, 34b emerging from an associated, horizontally extending hydraulic cylinder36 a, 36 b.

The cutting device 6 also comprises a first cutting knife 38 a and aparallel, second cutting knife 38 b. Both cutting knives 38 a, 38 b aredirected vertically inwards toward the cutting area 28 and may be movedin this direction for cutting of the first chain link 30 within thecutting area 28. In this embodiment, the contact surface of the firstcutting knife 38 a is comprised of a third cutting knife 38 c structuredfor cutting-cooperation with the first cutting knife 38 a, whereas thecontact surface of the second cutting knife 38 b is comprised of afourth cutting knife 38 d structured for cutting-cooperation with thesecond cutting knife 38 b. Thus, the first cutting knife 38 a and thethird cutting knife 38 c form a first set of cooperating cutting knives,whereas the second cutting knife 38 b and the fourth cutting knife 38 dform a second set of cooperating cutting knives. In this context, theedges of the first and the third cutting knife 38 a, 38 c, and also theedges of the second and the fourth cutting knife 38 b, 38 d, are aligneddirectly opposite each other. Thereby, the first and third cutting knife38 a, 38 c may cooperate in order to cut the first side 30 a of thechain link 30, whereas the second and fourth cutting knife 38 b, 38 dmay cooperate in order to cut the second side 30 b of the chain link 30.

In order to be moved vertically inwards toward the cutting area fromabove, the first and second cutting knife 38 a, 38 b is connected to ahydraulic power pack 40 placed on said platform 22, whereby the powerpack 40 is moveable along the deck 4 via said rails 24, cf. FIGS. 3 and4. The power pack 40 comprises, among other things, four vertical andpowerful hydraulic cylinders 42 a, 42 b, 42 c and 42 d with associated,powerful piston rods 44 a, 44 b, 44 c and 44 d emerging therefrom in anupward direction. At their upper ends, the piston rods 44 are connectedto a joint frame structure 46. A guillotine-resembling knife base 48 isconnected to the underside of the frame structure 46 and extendsvertically down therefrom. The first and second cutting knife 38 a, 38 bis attached to the underside of the knife base 48 and at a distance fromeach other. The underside of the knife base 48 also comprises a recess50 arranged between the knives 38 a, 38 b in order to accommodatevertically standing chain links during advancement or cutting of thechain 10.

Further, said third and fourth cutting knife 38 c, 38 d is structured ina manner allowing it to move, to some extent, vertically upwards towardthe cutting area 28 for severing engagement with its respective side 30a, 30 b of the chain link 30. In order to be moved vertically inwardstoward the cutting area from below, the third and fourth cutting knife38 c, 38 d is disposed at the upper end of its respective and verticalhydraulic cylinder 52 a and 52 b also placed on said platform 22.

Moreover, FIGS. 3, 4, 6, 8 and 10 show a special embodiment wherein thecutting device 6 also comprises a fixing device 54 for fixing of avertically standing, second chain link 56 in the chain 10 when thehorizontally lying, first chain link 30 is severed in the cutting device6. Such a fixing of the chain 10 is capable of preventing a potentiallydamaging backlash of the chain 10 upon being severed. In thisembodiment, the fixing device 54 is activated and operated interactivelyvia remote control. For this purpose, the same surveillance camera andlight source (not shown), among other things, is used as that mentionedfor interactive movement of the platform 22. It is stressed, however,that such a fixing device 54 is not a prerequisite for allowing thecutting device 6 to work as intended.

As an alternative or addition, the activation and movement of the fixingdevice 54 relative to the chain 10 may be carried out more or lessautomatically by means of suitable control technological auxiliarymeans. Thus, the fixing device (or the cutting device 6) may be providedwith a sensor device, for example a pivotal arm provided with an outerwheel or guide, or a sensor, for example a laser meter, structured in amanner allowing it to record the distance between a reference point andchain links in the chain 10. This distance will vary depending onwhether the distance is measured to a vertically standing or ahorizontally lying chain link in the chain 10, and depending on theposition of the particular chain link relative to said reference point.On the basis of such varying distance measurements, it is possible toestablish distance measurements corresponding to correct positions of asecond chain link 56 relative to the fixing device 54. When in suchcorrect positions, the fixing device 54 may be activated for engagementwith the second chain link 56 (cf. FIG. 8). By so doing, it is alsopossible to establish distance measurements corresponding to incorrectpositions of a second chain link 56 relative to the fixing device 54(cf. FIG. 6). When in such incorrect positions, the fixing device 54 isnot activated. However, a movement of said platform 22 is activated,whereby the fixing device 54 and the cutting device 6 are moved parallelto the chain 10 until said sensor device records a correct position ofthe fixing device 54 relative to the second chain link 56. Then themovement of the platform 22 is stopped and the fixing device 54 isconveyed inwards toward the second chain link 56 for fixing engagementtherewith (cf. FIG. 10). In advance, said distance informations havebeen entered into a database affiliated with a suitable processor withan associated control program and -equipment for control of themovements of the platform 22 and the fixing device 54.

Similar to the induction coil devices 32 a, 32 b, the fixing device 54comprises a first gripping element 58 a and an oppositely directed,second gripping element 58 b, both of which are directed horizontallyinwards toward the chain 10 and the second chain link 56 to be fixed bythe gripping elements 58 a, 58 b. The gripping elements 58 a, 58 b arestructured so as to be moveable along a respective rail 60 a, 60 bplaced on said platform 22, and between the cutting device 6 and theguide wheel 8. Each gripping element 58 a, 58 b is also connected to amoving means (not shown, for example a piston, a pitch rack guide orsimilar, for allowing the gripping element 58 a, 58 b to be movedhorizontally relative to the chain 10. Furthermore, each grippingelement 58 a, 58 b is of a shape that fits in between two successive,horizontal chain links. The gripping surface on each gripping element 58a, 58 b is also of a shape that fits within the inner opening of thevertically standing, second chain link 56, and which fits around arespective side of a transverse strut beam 62 disposed within saidopening and between the side of the chain link 56, as shown in FIG. 10.Moreover, each chain link is provided with such a strut beam 62. Theprimary object of the strut beam 62 is to prevent collapse of the chainlink when being gripped and advanced via the guide wheel 8 and thecabelar wheel (not shown).

Reference is now made to FIGS. 5-13 for description of the advancementand cutting of the chain 10.

FIGS. 5 and 6 show the chain 10 whilst being conveyed past the cuttingdevice 6 and the fixing device 54. When in this position, the inductioncoil devices 32 a, 32 b, the cutting knives 38 a, 38 b, 38 c, 38 d andalso the gripping elements 58 a, 58 b are inactive and not in contactwith the chain 10.

FIGS. 7 and 8 show the chain 10 when the second chain link 56 is locatedhalfway between the gripping elements 58 a, 58 b and immediately beforethey are activated and conveyed inwards toward the chain link 56 forgripping and fixing thereof. When in this position, the induction coildevices 32 a, 32 b and the cutting knives 38 a, 38 b, 38 c, 38 d arestill inactive and not in contact with the chain 10.

FIGS. 9 and 10 show the chain 10 after having conveyed the grippingelements 58 a, 58 b into the opening in the second chain link 56, andaround each respective side of said strut 62, whereby said chain link 56is fixed in place. By so doing, the first chain link 30 to be cut alsoremains stationary within the cutting area 28 of the cutting device 6.Disposed in this position, said two induction coil devices 32 a, 32 bhave been conveyed inwards and bear against the respective sides 30 a,30 b of the horizontally lying, first chain link 30. FIGS. 9 and 10 alsoshow the induction coil devices 32 a, 32 b whilst in the process ofheating the sides 30 a, 30 b of the chain link 30. When in thisposition, the cutting knives 38 a, 38 b, 38 c, 38 d are still inactiveand not in contact with the chain 10.

FIG. 11 shows the subsequent step wherein the cooperating knife set 38a, 38 c and the cooperating knife set 38 b, 38 d have been activated andhave severed the first side 30 a and the second side 30 b, respectively,of the horizontally lying, first chain link 30. In this context, thehydraulic power pack 40 has been activated in order to convey the pistonrods 44 a, 44 b, 44 c and 44 d, and hence the knife base 48 and itsparallel cutting knives 38 a, 38 b, downwards toward the cutting area 28and the chain link 30.

At the same time, the vertical hydraulic cylinders 52 a, 52 b, which aredisposed below the chain link 30, have been activated for conveying itsattached and opposite cutting knives 38 c, 38 d upwards toward thecutting area 28 and the chain link 30. During the very severing, theinduction coil devices 32 a, 32 b may be retracted from the chain link30, or they may still be placed partially around the respective sides 30a, 30 b of the chain link 30. In the latter case, the induction coildevices 32 a, 32 b may become destroyed by the cutting knives 38 a, 38b, 38 c, 38 d which, however, is of secondary importance given that thedevices 32 a, 32 b may be readily replaced. The tensile load acting,during the cutting operation, on the chain link 30 due to the weight ofthe chain 10 and the anchor 16 in the sea 14, will also contribute toweaken the chain link 30 faster and further, which increases theeffectiveness of the cutting operation. This tensile load will also beable to pull the severed chain 10 over the stern 12 of the vessel 2 anddown into the sea 14 after the cutting of the chain link 30.

An enlarged section of the cutting position according to FIG. 11 isshown in FIG. 12.

FIG. 13, however, shows the cutting knives 38 a, 38 b, 38 c, 38 d afterbeing retracted from the cutting area 28. Thereby, complete cut surfaces64 a, 64 b on the respective sides 30 a, 30 b of the chain link 30become visible.

1. A cutting device for mechanical cutting of a line extending from afloating vessel, wherein the cutting device is structured for placementon the vessel and comprises: at least one guide structured fordirectional steering of the line past a cutting area for the line; andat least one cutting knife structured for cutting of the line within thecutting area, wherein the line comprises a load-burdened chain composedof chain links extending from the floating vessel; wherein the cuttingdevice is structured for mechanical cutting, hence weakening, of aload-burdened chain link located within the cutting area; wherein thecutting device, for said mechanical cutting, comprises: at least onefirst, moveable cutting knife with an opposite contact surfacestructured for cutting of a first side of the chain link located withinthe cutting area; and at least one second, moveable cutting knife withan opposite contact surface structured for cutting of a second side ofthe chain link located within the cutting area; and wherein the firstcutting knife and the second cutting knife are arranged parallel to eachother so as to allow them to move in parallel during cutting of thechain link; said load on the chain stretching the chain link so as tocontribute, during cutting thereof, to weaken the chain link faster andfurther until the chain link is severed.
 2. The cutting device accordingto claim 1, wherein the first cutting knife and the second cutting knifeare connected to at least one moving means structured to be moveableinwards toward the cutting area for the chain link.
 3. The cuttingdevice according to claim 2, wherein said moving means comprises atleast one of the following means: a moveable piston; and a pitch rackguide.
 4. The cutting device according to claim 1, wherein the firstcutting knife and the second cutting knife are vertically arranged. 5.The cutting device according to claim 1, wherein said contact surface iscomprised of a planar surface.
 6. The cutting device according to claim1, wherein the contact surface of the first cutting knife is comprisedof a third cutting knife structured for cutting-cooperation with thefirst cutting knife, whereas the contact surface of the second cuttingknife is comprised of a fourth cutting knife structured forcutting-cooperation with the second cutting knife.
 7. The cutting deviceaccording to claim 6, wherein the first cutting knife and the thirdcutting knife are aligned directly opposite each other for cutting ofthe first side of the chain link, whereas the second cutting knife andthe fourth cutting knife are aligned directly opposite each other forcutting of the second side of the chain link; and wherein the thirdcutting knife and the fourth cutting knife are arranged parallel to eachother.
 8. The cutting device according to claim 6, wherein the thirdcutting knife is structured to be moveable toward the first cuttingknife, whereas the fourth cutting knife is structured to be moveabletoward the second cutting knife.
 9. The cutting device according toclaim 8, wherein the third cutting knife and the fourth cutting knifeare connected to at least one moving means structured to be moveableinwards toward the cutting area for the chain link.
 10. The cuttingdevice according to claim 9, wherein said moving means comprises atleast one of the following means: a moveable piston; and a pitch rackguide.
 11. The cutting device according to claim 6, wherein the thirdcutting knife and the fourth cutting knife are vertically arranged. 12.The cutting device according to claim 1, wherein the cutting device alsocomprises at least one fixing device for fixing of the chain duringcutting thereof.
 13. The cutting device according to claim 1, whereinthe cutting device is structured for remote-controlled activation andoperation.
 14. The cutting device according to claim 1, wherein thecutting area is placed on or near a deck on the floating vessel.
 15. Amethod for mechanical cutting of a line extending from a floatingvessel, wherein the method comprises: (A) placing at least one cuttingdevice on the vessel, wherein the cutting device comprises: at least oneguide structured for directional steering of the line past a cuttingarea for the line; and at least one cutting knife structured for cuttingof the line within the cutting area; (B) conveying the line through saidguide and cutting area; and (C) when cutting of the line is required,activating said cutting knife and severing the line within the cuttingarea, wherein the method also comprises: using a line comprising aload-burdened chain composed of chain links extending from the floatingvessel; in step (A), using a cutting device structured for mechanicalcutting, hence weakening, of a load-burdened chain link located withinthe cutting area, wherein the cutting device, for the purpose of saidmechanical cutting, comprises: at least one first, moveable cuttingknife with an opposite contact surface; and at least one second,moveable cutting knife with an opposite contact surface; said firstcutting knife and second cutting knife arranged parallel to each other;in step (B), conveying the chain through said guide and cutting area,said cutting area located between said cutting knives and said oppositecontact surface; and in step (C), activating said first cutting knifeand moving it toward its opposite contact surface until severing a firstside of the chain link, and also activating said second cutting knifeand moving it toward its opposite contact surface, and in parallel withthe first cutting knife, until severing a second side of the chain link;said load on the chain stretching the chain link so as to contribute,during cutting thereof, to weaken the chain link faster and furtheruntil the chain link is severed.
 16. The method according to claim 15,comprising activating and operating the cutting device by means ofremote control.
 17. The method according to claim 15, comprising placingthe cutting area on or near a deck on the floating vessel.
 18. Use of acutting device according to claim 1 is for mechanical cutting of a lineextending from a floating vessel.